Improve the optional translation of quotes

Fix several problems with the recently-added custom variable
help-quote-translation where the code would quote inconsistently
in help buffers.  Add support for quoting 'like this', which
is common in other GNU programs in ASCII environments.  Change
help-quote-translation to use more mnemonic values: values are now the
initial quoting char, e.g., (setq help-quote-translation ?`) gets the
traditional Emacs help-buffer quoting style `like this'.  Change the
default behavior of substitute-command-keys to match what's done in
set-locale-environment, i.e., quote ‘like this’ if displayable,
'like this' otherwise.
* doc/lispref/help.texi (Keys in Documentation): Document
new behavior of substitute-command-keys, and document
help-quote-translation.
* doc/lispref/tips.texi (Documentation Tips):
Mention the effect of help-quote-translation.
* etc/NEWS: Mention new behavior of substitute-command-keys,
and merge help-quote-translation news into it.
When talking about doc strings, mention new ways to type quotes.
* lisp/cedet/mode-local.el (overload-docstring-extension):
Revert my recent change to this function, which shouldn't be
needed as the result is a doc string.
* lisp/cedet/mode-local.el (mode-local-print-binding)
(mode-local-describe-bindings-2):
* lisp/cedet/srecode/srt-mode.el (srecode-macro-help):
* lisp/cus-theme.el (describe-theme-1):
* lisp/descr-text.el (describe-text-properties-1, describe-char):
* lisp/emacs-lisp/cl-generic.el (cl--generic-describe):
* lisp/emacs-lisp/eieio-opt.el (eieio-help-class)
(eieio-help-constructor):
* lisp/emacs-lisp/package.el (describe-package-1):
* lisp/faces.el (describe-face):
* lisp/help-fns.el (help-fns--key-bindings)
(help-fns--compiler-macro, help-fns--parent-mode)
(help-fns--obsolete, help-fns--interactive-only)
(describe-function-1, describe-variable):
* lisp/help.el (describe-mode):
Use substitute-command-keys to ensure a more-consistent quoting
style in help buffers.
* lisp/cus-start.el (standard):
Document new help-quote-translation behavior.
* lisp/emacs-lisp/lisp-mode.el (lisp-fdefs):
* lisp/help-mode.el (help-xref-symbol-regexp, help-xref-info-regexp)
(help-xref-url-regexp):
* lisp/international/mule-cmds.el (help-xref-mule-regexp-template):
* lisp/wid-edit.el (widget-documentation-link-regexp):
Also match 'foo', in case we're in a help buffer generated when
help-quote-translation is ?'.
* src/doc.c: Include disptab.h, for DISP_CHAR_VECTOR.
(LEFT_SINGLE_QUOTATION_MARK, uLSQM0, uLSQM1, uLSQM2, uRSQM0)
(uRSQM1, uRSQM2, LSQM, RSQM): New constants.
(Fsubstitute_command_keys): Document and implement new behavior.
(Vhelp_quote_translation): Document new behavior.

1 files changed, 14 insertions, 9 deletions

diff --git a/etc/NEWS b/etc/NEWS
index 1611c7a7926..bab1b41e759 100644
--- a/etc/NEWS
+++ b/etc/NEWS
@@ -845,11 +845,16 @@ when signaling a file error.  For example, it now reports "Permission
 denied" instead of "permission denied".  The old behavior was problematic
 in languages like German where downcasing rules depend on grammar.
 
-** (substitute-command-keys "`foo'") now returns "‘foo’".
-That is, it replaces grave accents by left single quotation marks, and
-apostrophes that match grave accents by right single quotation marks.
-As before, isolated apostrophes and characters preceded by \= are
-output as-is.
+** substitute-command-keys now replaces quotes.
+That is, it replaces left single quotation marks (‘) by left quotes
+and right single quotation marks (’) by right quotes.  It also
+replaces grave accents by left quotes, and apostrophes that match
+grave accents by right quotes.  As before, isolated apostrophes and
+characters preceded by \= are output as-is.  Left and right quotes are
+determined by new custom variable ‘help-quote-translation’.  ?‘ means
+quote ‘like this’, ?' means quote 'like this', ?` means quote `like
+this', and nil (default) means quote ‘like this’ if displayable and
+'like this' otherwise.
 
 +++
 ** The character classes [:alpha:] and [:alnum:] in regular expressions
@@ -956,10 +961,10 @@ directory at point.
 ** Documentation strings now support quoting with curved single quotes
 ‘like-this’ in addition to the old style with grave accent and
 apostrophe `like-this'.  The new style looks better on today's displays.
-When an old-style string is copied to a help buffer it is converted to
-the new style.
-
-** New option `help-quote-translation'.
+In the new Electric Quote mode, you can enter curved single quotes
+into documentation by typing ` and '.  Outside Electric Quote mode,
+you can enter them by typing ‘C-x 8 [’ and ‘C-x 8 ]’, or (if your Alt
+key works) by typing ‘A-[’ and ‘A-]’.
 
 +++
 ** Time-related changes: